Process of treating keratinous materials



FIPSEU? XR faienteci May its REFERENCE rnocnss or TREATING KiiaATmoUsMATERIALS Milton Harris, Bethesda, Md., and Alfred E. Brown, Washington,D. 0., assignors to Harris Research Laboratories, Washington, D. C., a.

partnership N Drawing. Application October 7, 1946,

Serial No. 701,623

8 Claims. 1

The present invention relates to the treatment of keratinous' materials,such as wool, hair, fur and the'like, and to the product of suchtreatment. E

Thesematerials are characterized by the presen'ce therein of keratin, afibrous protein containing amino acids including cystine. amino acidsarejoined together by peptide linkages to form protein chains and theresultingchains are cross linked by the disulfide group (-SS) ofcystine.

It is an object of the invention to provide an improved process fortreating keratinous materials. A further object is to provide aprocessfor stripping color from wool and like materials.

Yet another object is to produce a modified keratinous material havingimproved-chemical properties combined with substantially unimpairedphysical properties.

ucts such as shoddy, clippings, rags and the like, for reprocessing, itis necessary to remove the dye or color from the wool. The present-daypractice is to strip colors from wool in acidic media with sodium orzinc formaldehyde sulfoxy late. This treatment adversely afiects themechanical as well as the chemical properties of the wool even when theprocessing conditions are carefully'controlled. Both the wet and drytensilestrength are decreased, especially the former, and often the woolacquires a dead'and harsh hand as compared with the untreated material.types of colors which are more difiicult to strip ping agent or theduration of the treatment must be increased. In some cases a secondstrip is The 'One application of theinvention is in the stripping ofcolor from wool. In preparing wool prod- This problem is accentuatedwith (ore- 102)" f p and with which the concentration of thestripessential to remove the color and in these cases chemical damage tothe wool is further increased. Wool products stripped by theseconventional procedures also show an increased susceptibility to damagewhen treated under oxidizing,

reducing or alkaline conditions in subsequent processing.

By the process of the present invention it is possible not only to stripcolor from wool without substantial impairment of the mechanicalproperties .of the wool, but, quite apart from stripping. our process isuseful in treating wool to improve its chemical properties and enhanceits resistance to attack by oxidizing, reducing and alkaline agents.

In accordance with the invention, the kerati nous material is subjectedto the action of areducing agent for keratm in the presence Oran.

alkylene. dihalide.

The action of reducing agents on keratinous material ordinarily resultsin rupture of disulfide linkagesand damage to the fiber. In our process,

however, the linkages ruptured by the reducing agent are immediatelyrebuilt with the formation o'fne'w'stable linkages. We provide aneffective,

commercially practical process for replacing relatively unstablechemical bonds of keratinous material's'v'vith new chemical linkageswhichare', resistant to the action of oxidizing, reducing and alkalineagents.

The invention is illustrated by the following examples of proceduresrby.which it maybe pu into practice: s

. Ezamplel 1.5: parts of 1, 2'-dichloroethane are dispersed inflf flparts of borate solution adjusted to pH 8.6. 7.5 parts of sodiumsulfoxylate-formaldehyde are dissolved in themixture, after which" 15parts of wool are immersed'in the liquid. The" temperatureis raised toC. and held for one hour, after which the wool is removed, rinsed and riV 7 Example 2 T9.-8 parts by weight of 1, 2-dibromoethane'are dispersedin '3000 parts of 1% borax by means of a small amount of a quaternarysalt of a substituted fatty acid amide available commercially under thetrade'name Sapamine KW. Any good dispersing agent'may be'used. 5 partsof sodium h'ydrosulfite are 'dissolvedin the mixture, after whichl00parts of colored flannel rags are im- Inersed in the liquor,-and themixture is kept at the boil for 15 30minutes. The wool is then rinsedanddried. The color is stripped from the wool by this treatment.

I tdmp e "1.5 parts'of l, -2-dibromoethane are dispersed in-450 partsof'borate buffer, pH 8.6, after which 0.7 part of sodium hydrosulflteare added. 15 parts of old red knits are'added. The mixture is treatedat '80 C. for 30-60 minutes, after which I the wool is rinsed and dried.The color is stripped from the wool by this treatment.

Example 4 31.6 parts of 1,2-dibromoethane are dispersed in 4800 parts ofwater adjusted to pH 8.3 with borate solution. A convenient procedureisto" use' the required amount of a concentrated dis-y persionof1,2-dibromo'ethane in water which can Example 45 parts of1,2-dibromoethane are dispersed in 11,500 parts of water and the pHadjusted to 8.5 with borate buffer, after which '45 iof sodiumhydrosulfite are added. 455 parts of wool cloth are added to thismixture. The entire mixture is then heated at 90-95 C. for oiiehour,after which the wool isrinsed and dried. The cloth is bleachedli'ghtlyby this treatment. This treatment is also suitable foruse'with'raw wool stock.

"Example 6 1.5 parts of 1, 2-dibromoethaneare dispersed in .450 parts ofborate buffer, pH;8. 2, after which 0.7 part offormamidinesulfinicacidare added. parts of blue serge rags arethenaddedand h mixture is treat d $11 1 0.1 IQ! 30150 utes, after whichthe wool is rinsed anddried. The color is stripped from the serge bythis treatment.

Example 7 '1.3 "parts of 1,2-"dibromoethane are dispersed in 420 partsof 0.3 molar boratestilution, by means of cetyl dimethylbenzyl ammoniumchloride available commerciallyuncler the trade name ri on K-fiO, and 0.ar isOG Q K YE Sir formaldehyde are thendissolved. in the mixture. lip-as o pas e sweate w r te s i in -$4.??? immersed in the mixture and thereaction carried out at the lboilro .3 to .60 min s. a er e ail the. o hs washedand dri d- -f-F afi9 0 is stripped from the worsteds by thistreatment.

In general, the alkylenedihalides employed as alkylating agents in theforegoing examples are not completely miscible in water. It isadvantageous in practice first to iorma concentrated dispersionef thealkyla-t-ing. agent in :water by the use of small amountsof suitabledispersing-agents such as those available commercially under the tradenames of- Sapamine KW, Triton K-60, Span 60, Tween 60, and otherdispersing agents having a similar action. Thisiconcentrateddispersionis thenadded inappropriate'amount to the solution containing thereducing agent, thus forming a suitable 'b'athfor the practice of ourinvention. y

The process of the invention is subject to variation, for example in thereducing and alkylating agents used and the --concen'tration thereon-thetime of treatment, the temperature and pH of the bath, etc. 7

Examples oisuitable reducing agents are the varioussulfoxylate-formaldehyde compounds, the 'hydrosulfites, formamadine'sulfinic "acid and the like. Other reducing agents may beused, but theyshould be or a type which does not react with thealkylating agent (aswould thiol compounds such, for "example, as fthioglycolic ecid andsalts thereof, monothioethylene*glycol, an t ther mercaptans) sinceotherwise "the two cbmponents for 'thesolution would beexliausted byreaction with -each"other and would notice 4 available for reaction withthe wool. The term reducing agent as used in the claims includessulfoxylate formaldehyde compounds, hydrosulfites, formamidinesulfinicacid, and such other reducing agents for keratin asdo not react with'alkylene dihalides.

In the case of stripping processes, the choice of reducing agent willdepend on the cost and the quality of the strip and will also dependupon the type of 'dye or color to be removed. Small scale trials willquickly indicate the best set of conditions to use for. any given batchof goods. In some 'casesia much better strip can be obtainedbyfirstgivin'g the wool an ammonia scour, for

example with "2% to 5% of ammonia on the weight, of the wool for thirtyminutes at 50" toIGOI C.

The amount of reducing agent employed may be varied over wide limits, upto or more on the weight of the wool, with no appreciable effect on theproperties of the. modified 'wool p'roduced. In stripping. processes, ingenerali-3 to5% of 'the reducingag'ent'onthe weight ofthe wool will givean effective stripping action. Larger amounts may be .present in .thereaction mixture without significant, :adverse effect on the quality ofthe stripped. product. .With :colors which are difficult "to strip, itis advantageous to add the reducing :agent "in'increments "at :the boil,since maximum "reducing epowerzfor strip-e ping purposes is thusutilized.

Suitable alkylating a'gents are fthealkylerie' fiihalides andsubstituted and modifie'dallwlene dihali'des, f'or example, methylenerdibromide, methylene cliic xzlide, methylene ibromoiodide, eth-' ylenedibromide, "ethylene dichloride, .ethylerie chlorobromide, trimethylene'dibromide,.-:1L4-:-di-. bromobutane, --1;4-dichloro-2 butene,.2,2=di'chlo-' rodiethyl ether, 4,4'-chloromethyl 'diphenyl rand2,2-dibromodiethyl ether. The term falkylene dihal-ide as used;in 'th'eclaims'zinclud'es substituted and modified'alkylene dihalides.

Very little alkylating agent is required; .as'little. as 0:00045 mol ofalkylatin'g agent per gram of, wool gives -good results. riihargeramountsnhave no deleterious efiect.

. It hasbeen found desirable to maintain the pr: of the'solution at 7 orabove and-preferably at pH 8-10. Adjustment of "the pH "to :the value.desired :can be made, :for example, with alkaline. salts suchas borateor aphosphate buffer or=with borax.

The liquor-wool :ratio may be varied over ea. wide range Withlnosignificant difierencesrinthe proportion of the wool wderivativeziormed.We prefer to employ liquor-wool ratios between about. 10 to land 40toil.

The process f'isop'erative and reflective within a wide rangeoitemperatures. We prefer to carry out the "treatment" at temperaturesbetween-about 60 C. -an'd.100"C.

The duration of the treating timemay-be-varied considerably. *Afterthedesired amount ofimod'ie fication :of the keratinousmaterialvhasoccurred,- iurther treatment will not significantlyzchange theproperties of thermodified keratin product. In general, treatment'forabout one-half h'ourto one hour at 380 C. prziro'm-yabout one-quarterhour' to one hour-atfthe iboilgives goodresults;

With the proiuer-iameuht 70f alkylating agent present, thetnumber oistabilized linkages that can be formed in :the'fiber will"depend'on'the'. concentration of reducing agent, "-theupll' of thesolution and "the temperature and duration iiof the treatment. 1The'keratinousprdductsitreated:

muss Kill iiiilli iUt in accordance with our invention exhibitsignificantly enhancedresistance to deterioration when exposed tooxidizing, reducing or alkaline agents. At the same time the mechanicalproperties of the wool are substantially unimpaired and are comparableto those of untreated Woo1..

It has been proposed to treat keratin with a reducing agent andsubsequently to treatthe resulting product with an alkylating agent.This treatment, however, results in a product essentially diiferent fromand markedly inferior to that obtained by our invention, when the samereducing agents are used. In the two-step process, deterioration of thefiber produced by the reducing agent persists in the final product to asubstantial extent. Th subsequent treatment with an alkylating agent isnot capable of restoring to the keratin its original properties.

While our invention is not limited to any theory of operation, it issuggested that the alkylating agent in the reducing solution, by formingstable linkages. immediately upon rupture of the disulfide linkages,preserves the physical properties of the material.

When keratinous material is treated with reducing agent alone, under theconditions of. our treatment, a substantial number of sulfhydryl groupsis formed, as indicated by a strong nitroprusside reaction. Themechanical properties of wool so treated are markedly inferior to thoseof the untreated productits tensile strength is greatly weakened and thefabric becomes stiff and boardy. In our process, however, thedetrimental effects noted with reducing agent alone are negligible.

Our process is capable of easy control. It is relatively insensitive tosmall variations in conditions such as temperature, concentration ofreagents, time of treatment, etc. No damage is caused either by highconcentrations of reducing agent or by unduly prolonged treatment.

We claim:

1. The process for modifying a keratino-us material to increase itsresistance to attack by oxidizing agents, reducing agents and alkaliswhile preserving substantially unimpaired its mechanical properties,which comprises treating the keratinous material at a temperaturebetween 60 C. and 100 C. and a pH above 7, in a liquid bath containing3% to 100% of the weight of the keratinous material of a reducing agentfor keratin which is inert to alkylene dihalides, to rupture disulfideacross linkages of the keratinous material, said bath also containingmorethan 0.00045 mol per gram of keratinous material'of an alkylenedihalide, whereby, new stable alkylene cross linkages between thepeptide chains of the keratin are formed immediately. upon rupture ofthe disulfide linkages.

2. The method of stripping color from dyed wool while preservingsubstantially unimpaired the mechanical properties of the wool andincreasing the resistance of the Wool to attack by oxidizing agents,reducing agents and alkalis, which comprises treating the wool at atemperature between C. and 100 C. and a pH above 7, in a liquid bathcontaining 3% to 100% of the weight of the wool of a reducing agent forkeratin which is inert to alkylene dihalides and which is a strippingagent for dyestufi on wool, to rupture disulfide cross linkages of thewool and simultaneously strip the dyestufi, said bath also containingmore than 0.00045 mol per gram of wool of an alkylene dihalide; wherebynew tide chains ofthe woolare formedimmediately upon rupture of thedisulfide linkages. 7

H3. The method of removing color from wool while presenvingsubstantially unimpaired the mechanical properties of the wool andincreasing the resistance of the wool to attack by oxidizing agents,reducing agents and alkalis which comprises treating the wool at atemperature between 60C. and C. and a pH above 7, ins, liquid bathcontaining 3% to 100% of the Weight of the wool of a keratin reducingagent selected from the class consisting of sulfoxylate formaldehydecompounds, hydrosulfites and f ormamidine sulfinic acid, to rupturedisulfide cross linkages of the wool and simultaneously remove color,said bath also containing more than 0.00045 mol per gram of wool of analkylene dihalide, whereby new stable alkylene cross linkages betweenthe peptide chains of the wool are formed immediately upon rupture ofthe disulfide linkages. i

4. The method of stripping color from dyed wool while preservingsubstantially unimpaired the mechanical properties of the wool andincreasing the resistance of the wool to attack by oxidizing agents,reducing agents and alkalis, which comprises treating the wool at atemperature between 60 C. and 100 C. and a pH above 7, in a liquid bathcontaining 3% to 100% of the Weight of the wool of a keratin reducingagent which is a dyestufi stripping agent selected from the classconsisting of sulfoxylate formaldehyde compounds, hydrosulfites andformamidine sulfinic acid, to rupture disulfide cross linkages of thewool and simultaneously strip the dyestufi, said bath also containingmore than 0.00045 mol per gram of wool of 1,2-dibromoethane, whereby newstable alkylene cross linkages between the peptide chains of the woolare formed immediately upon rupture of the disulfide linkages.

5. The method of stripping color from dyed wool while preservingsubstantially unimpaired the mechanical properties of the wool andincreasing the resistance of the wool to attack by oxidizing agents,reducing agents and alkalis, which comprises scouring the wool with 2%to 5% of its weight of ammonia at a temperature between 50 C. and 60 C.and then treating the wool for from hour to 1 hour at a temperaturebetween 60 and 100 C. and a pH above 7, in a liquid bath containing 3%to 100% of the weight of the wool of a reducing agent selected from theclass consisting of sulfoxylate formaldehdyde compounds, hydrosulfitesand formamidine sulfinic acid, to rupture disulfide cross linkages ofthe wool and simultaneously strip the dyestuii, said bath alsocontaining more than 0.00045 mol per gram of wool of an alkylenedihalide, whereby new-stable alkylene cross linkages between the peptidechains of the wool are formed immediately upon rupture of the disulfidelinkages.

6. The method of removing color from wool while preserving substantiallyunimpaired the mechanical properties of the wool and increasing theresistance of the wool to attack by oxidizing agents, reducing agentsand alkalis which comprises treating the wool at a temperature between60 C. and 100 C. and. a pH above 7, in a liquid bath containing 3% to100% of the weight of the wool of sodium sulfoxylate formaldehyde, torupture disulfide cross linkages of the wool and simultaneously removecolor, said bath also containing more than 0.00045 mol per gram of woolofan alkylene dihalide, whereby new stable alkylene cross linkagesbetween the pep- 1 stable alkylene cross linkages between the pep,

RQQit tide' chmns ()Nihe Wo61' "are iofmdifififidihtefy upon ruptureefth'e' fl istfifide'iirikegesr 7. The method bfrein'o'vin'g @0101 mm woolwhile preserving slibstantia'liy uni' 'mpaired the mechanicalproperti'es' of the W001 andincreaving the resistance-DY the W001teattabkby oxidiz ing agents} reducing agents anflmlkalij Whiehcomprise's treating the W601 hth temperature between 60' C. and 100 C;and a/pH zitvtimri 7 ,''in a liquid bath cor itaining -3%-- to 100% oTbh'e weight of "the wool-0f sodium 'hydrosfilflfit'e to rupturediSuIfide cre's' linkages 6f the wool-find simultaneously removecolbrfsaid belth "32186- 1261?- tamingmo're than 0.00045 moi-per gram efwbel of an -alky1ene-diha,1ide, whereby new stable alkylene linkagesbetween me peptide chains of the W601 are formed immediately upenrupture of the distilfid linkages. '8. The method of removing 60161--from W601 While preserving "substantially hhimiifiird the mechanicalproperties of the wool gnd increasing the resistance of the W001to-attack by oxidizing agefits,-reducing agents and alkal is, which compri'ses treating the wool elt & iaemperasurebetw'en 60 C. and 100 C-.and-a pH above 7, in a liquid bath containin'g-3% $0 100% of theWeight'df the

1. THE PROCESS FOR MODIFYING A KERATINOUS MATERIAL TO INCREASE ITSRESISTANCE TO ATTACK BY OXIDIZING AGENTS, REDUCING AGENTS AND ALKALISWHILE PRESERVING SUBSTNATIALLY UNIMPAIRED ITS MECHANICAL PROPERTIES,WHICH COMPRISES TREATING THE KERATINOUS MATERIAL AT A TEMPERATUREBETWEEN 60*C. AND 100*C. AND A PH ABOVE 7, IN A LIQUID BATH CONTAINING3% TO 100% OF THE WEIGHT OF THE KERATINOUS MATERIAL OF A REDUCING AGENTFOR KERATIN WHICH IS INERT TO ALKYLENE DIAHALIDES, TO RUPTURE DISULFIDEACROSS LINKAGES OF THE KERATINOUS MATERIAL, SAID BATH ALSO CONTAININGMORE THAN 0.00045 MOL PER GRAM OF KERATINOUS MATERIAL OF AN ALKYLENEDIHALIDE, WHEREBY NEW STABLE ALKYLENE CROSS LINKAGES BETWEEN THE PEPTIDEAND CHAINS OF THE KERATIN ARE FORMED IMMEDIATELY UPON RUPTURE OF THEDISULFIDE LINKAGES.